diff options
| author | Denys Vlasenko <dvlasenk@redhat.com> | 2015-02-12 22:04:39 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-02-18 23:01:50 +0300 |
| commit | 8a764a875fe3cf3a83296bacd00bfc41917e95e2 (patch) | |
| tree | 49cfac09cb27568b93d8d384af495650e99988d9 | |
| parent | e07e0d4cb0c4bfe822ec8491cc06269096a38bea (diff) | |
| download | linux-8a764a875fe3cf3a83296bacd00bfc41917e95e2.tar.xz | |
x86/asm/decoder: Create artificial 3rd byte for 2-byte VEX
Before this patch, users need to do this to fetch vex.vvvv:
if (insn->vex_prefix.nbytes == 2) {
vex_vvvv = ((insn->vex_prefix.bytes[1] >> 3) & 0xf) ^ 0xf;
}
if (insn->vex_prefix.nbytes == 3) {
vex_vvvv = ((insn->vex_prefix.bytes[2] >> 3) & 0xf) ^ 0xf;
}
Make it so that insn->vex_prefix.bytes[2] always contains
vex.wvvvvLpp bits.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1423767879-31691-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/lib/insn.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c index 1313ae6b478b..5ea00ddc1825 100644 --- a/arch/x86/lib/insn.c +++ b/arch/x86/lib/insn.c @@ -164,6 +164,12 @@ found: /* VEX.W overrides opnd_size */ insn->opnd_bytes = 8; } else { + /* + * For VEX2, fake VEX3-like byte#2. + * Makes it easier to decode vex.W, vex.vvvv, + * vex.L and vex.pp. Masking with 0x7f sets vex.W == 0. + */ + insn->vex_prefix.bytes[2] = b2 & 0x7f; insn->vex_prefix.nbytes = 2; insn->next_byte += 2; } |